If I get your question correctly then you can see the buffers size limits in the BSC9131 QorIQ Qonverge Multicore Baseband Processor Reference Manual. It says that Rx memory buffer size (in bytes) is defined by a 24-bit field of register (see for RIQBS) while Tx memory buffer size (in bytes) is defined by a 16-bit field of register (see for TIQBS in the manual). So it limits the buffer size to 2^16 bytes.